From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy McNicoll Subject: Re: First steps with my Google Nexus-4 Date: Tue, 19 Jul 2016 03:52:25 -0700 Message-ID: <5d7a3050-4815-bb0d-a4df-7738ff96fb55@redhat.com> References: <8a85a158-a4f9-4ba5-0879-417f81370a19@redhat.com> <2412508.u5uv44vaGg@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46370 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753020AbcGSKwe (ORCPT ); Tue, 19 Jul 2016 06:52:34 -0400 In-Reply-To: <2412508.u5uv44vaGg@wuerfel> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Arnd Bergmann Cc: sedat.dilek@gmail.com, Rob Clark , Stanimir Varbanov , Andy Gross , David Brown , linux-arm-msm@vger.kernel.org, John Stultz , Bjorn Andersson On 2016-07-19 12:47 AM, Arnd Bergmann wrote: > On Monday, July 18, 2016 7:06:49 PM CEST Jeremy McNicoll wrote: >>> >>> [1] https://android.googlesource.com/device/google/debugcable/ >>> [2] http://www.contextis.com/resources/blog/kgdb-android-debugging-kernel-boss/ >>> [3] http://www.pabr.org/consolejack/consolejack.en.html >>> [4] http://www.offene-werkstaetten.org/werkstatt/fablab-neckar-alb-e-v >>> [5] http://tuebingen.linux.de/ >> >> [6] http://people.redhat.com/jmcnicol/nexus_debug/ >> >> No soldering needed, as its a skill I do not have. ;-) > > That sounds like it would grill the rx line, as the FTDI breakout > board you use supplies 3.3v while the expected input is 1.8v. > > As I understand it, you want to supply 3.3v to the microphone line > for detection but then run the rx/tx lines at 1.8v. I have not built > one of those cables myself yet, so I'm not sure. It probably works > using 3.3v, at least for a while, but there is a significant risk > of damaging the hw. I have been running this setup for a while without any issues, so too the Linaro folks in their lab. From what they tell me there have not been any issues thus far. /me is just a SW dude who fondles bits ;-) and not electricity. -jeremy